GL Quake was weird, culling front faces. Partly understandable, since
Quake's front order is clockwise and GL's default order is
counter-clockwise. However, since the order can be specified, that should
be done instead. Thus, specify the winding order as clockwise (for quake's
data), set culling for back-face removal, and then mess with the winding
direction in the mirror and fish-eye code.